Climate science at a glance
- The Arctic is warming twice to three times as fast as the global rate due to the unique features in the Arctic climate system—a phenomenon known as Arctic amplification.
- Evidence suggests that the warming of the Arctic is destabilizing the jet stream, forcing cold air from the polar regions to other, warmer regions closer to the equator, such as the United States.
- A warmer Arctic may be causing wintertime weather to get "stuck" more often, with cold air diving south and warm air heading north.
Arctic sea ice loss accelerates warming
The loss of Arctic sea ice increases the warming effect that is altering our climate. As the earth’s natural air conditioner, white sea ice moderates solar heating by increasing the reflectivity of Earth’s surface and decreasing the amount of heat that would otherwise by absorbed by darker ice-free Arctic seas.
The loss of the air conditioner effect creates a feedback loop that accelerates global warming. Melting sea ice also releases greenhouse gases from thawing permafrost and frozen methane from the ocean bottom. These feedback loops could have catastrophic consequences for the climate if triggered.
Regardless of approach, all projections indicate an eventual sea ice-free Arctic with continued emissions of greenhouses gases, threatening the invaluable ecosystem service the Arctic sea ice provides while simultaneously exacerbating global warming.
Arctic amplification and mid-latitude weather
The jet stream is powered by the temperature difference between the Arctic and the mid-latitudes, and this difference is shrinking as the Arctic warms. Scientists suspect this may be making the jet stream slow down and meander, contributing to an increase in unusual and extreme weather in the U.S. The channels through which Arctic warming affects mid-latitude weather is an active area of research.
Arctic amplification trends and climate change
- Over the last 50 years, for example, annual average air temperatures across Alaska and the Arctic have increased more than twice as fast as the global average temperature.
- Multiple observational studies suggest that Arctic amplification has caused concurrent changes in the Arctic and Northern Hemisphere large-scale circulation since the 1990s.
- Evidence suggests that Arctic amplification of global warming remotely affects mid-latitude regions such as the United States by promoting a weaker, wavier atmospheric circulation conducive to extreme weather.
- Research led by Dr. Jennifer Francis suggests that Arctic amplification has already led to weakened westerly winds and hence more slowly moving and amplified wave patterns and enhanced occurrence of blocking.
Studies attribute Arctic amplification to climate change
- (Van Oldenborgh 2016) analyze the Nov-Dec 2016 warm event at the North Pole and surrounding Arctic region and find it would have been extremely unlikely in a world without human-caused emissions of greenhouse gases and aerosols.
- (Lind et al. 2018) link the decline in imported sea ice in the Barents Sea from the mid-2000s to a sharp increase ocean temperature and salinity due to climate change. The resulting reduction in fresh water increases the ocean's ability to mix and increases heat near the surface, preventing sea-ice formation and increasing ocean heat content.